The present invention is directed to devices for ejecting biofluid drops, and more particularly to such devices designed to maximize usage efficiency and eliminate unintended contamination of the biofluid drops being ejected from the devices.
In existing drop ejection devices attention to fluid contamination has not been a high priority. For example, in the printing industry issues of contamination have focussed on avoiding unwanted mixing between different inks, in order to maintain intended ink color, and stopping debris from falling into the ink. However, in other environments avoiding contamination of the ejected fluid is a critical consideration. For example, many biological, genetic, pharmaceutical, medical, among other scientific tests, employ sequences or arrays of biofluid drops upon which the tests are to be performed. In these experiments, contaminated drops would result in unreliable, and therefore unusable test results.
In some testing applications several thousand biofluid drops are deposited onto a single substrate in the form of a biological assay. These biological assays will each contain a variety of unique biofluids. For example, in current biological testing for genetic defects and other biochemical aberrations, thousands of the individual fluids are placed on a glass substrate at different well-defined locations. Thereafter, additional depositing fluids may be deposited on the same locations. This printed biological assay is then scanned with a laser in order to observe changes in a physical property. In these situations, it is critical the drop ejection device not be a source of contamination or permit cross-contamination between biofluids. Thus, while existing drop ejection devices commonly employ a single fluid reservoir for multiple ejector mechanisms, this may not be an acceptable design for a drop ejection device emitting biofluids.
Further, the biofluids used in such experiments are extremely costly. In many existing drop ejection devices the volume of fluid in the reservoir and ejector assembly are much larger than what is required for making a biological assay. This unnecessary use of biofluids results in an increased cost of the test. Thus, existing processes for generating these testing sequences or arrays are time consuming, wasteful of the biofluids, of limited accuracy, and economically expensive.
It has, therefore, been determined to be desirable to provide a biofluid drop ejection mechanism which avoids contamination between the drop ejection mechanism and the biofluids, as well as cross-contamination between different biofluids. It is also considered desirable to provide a mechanism which is capable of delivering microvolumes of biofluid in a highly precise and efficient manner, and with differing amounts of volume dependant upon the biofluid being deposited and/or the intended use of the ejected drop.
A biofluid drop ejection unit for ejecting biofluid drops. A biofluid drop ejection mechanism of such a unit includes a transducer, which generates energy used to emit the biofluid drop. Further provided is a reagent cartridge or biofluid containment area which holds the biofluid. The reagent cartridge or biofluid containment area is configured to avoid contamination of the biofluid used to eject the biofluid drops. The reagent cartridge or biofluid containment area is in operational connection with the drop ejection mechanism such that upon operation of the drop ejection mechanism, biofluid drops are emitted. The drop ejection mechanism may be configured as a single piece disposable device with the biofluid containment area and transducer integrated, as well as a two-piece device with a transducer separate from a disposable cartridge.